Shock-absorber and the like.



W. R. RENO.

SHOCK ABSURBER ANU THE UKE.

' A PPLICAHQH HLED FEB. \5. 1911.

Patented Apr. 23, 1918,

w`|',1'.I1IAM. E. RENO, 0F LOUISVILLE, KENTUCKY.

SHOCK-ABSORBER AND THE LIKE.

Specification of Letters Patent.

Patented Apr. 23, 1918.

Application led February 1 5, 1917. Serial No. 148,730.

To all whom. it may concern:

Be it known that I, WILLIAM R. RENO, a citizen of the UnitedStates, residing at Louisville, county of J eiferson, and State of Kentuck have invented certain new and useful mprovements in Shock-Absorbers and the like, fully described and represented in the following specification and the accompanying drawings,y forming a' part of the same.

The resent invention relates particularly to shoe absorbers, but the invention is applicable also to other devices in which the movement of a spring or other moving member is to be checked or damped.

In the shock absorbers ,b 'therto known to me the mechanism was such that either the braking pressure was invariable 'or it was a function of the velocity, at any instant, of the device to be checked. By the first arran ement when the braking pressure is in-,`

variable, that is to say, constant for all shock' absorbing operations, there is either too llttle braking action for heav much for light shocks. Wit the second an rangement the value of the average braking effect is about one half that of the maxirlilm braking effect due to the initial velocity of the device to be checked. Consequently, in a shock absorber constructed on such aplan, more time is required to absorb a shock than if the pressure due to the maximum velocity of the device to be checked, was maintained throughout the braking period.

The object of the present invention is to provide a checking device particularl suitable as a shock absorber for vehic es by which the braking pressure shall, during any given braking operation, be substantiallyuniform, but will, if necessary, var for the different braking o erations accor ing to the initial velocity o the device to be checked. Asa consequence of this the de vice to be checked will have its ener absorbed more quickly than with the evices hitherto known, while at the same time the braking pressure will not exceed a reasonable maximum value appropriate for tle particular shock to be absorbed. A Vfurther object of the invention is to proullili lrdevice which will be exceedingly simple in construction and operation, and, hence, will require practically no attention.

With these general objects in view and others which will be obvious to those skilled in the art, from the description hereinafter,

shocks or toc the invention consists in the features, details of construction and combinations of parts which will first be described in oonnection with the accompanying drawings, and then particularly pointed out.

In the drawings- Figure 1 is a side elevation illustrating one embodiment of the invention applied to Aille axle and body of a vehicle where the spring is located ou top of the axle;

/ Fig. 2 is a transverse section partly in ele jvation, of one embodiment of the invention rin which a single wedge is employed;

Fig. 3 is a section on the line 3-3, Fig. 2; Fig. 4 is a section on the line 4 4, Fig. 2; Fig. 5 -is a detailed view illustrating a modification of the device suit able for attachment to a vehicle having its spring below the axle, and Fig. 6 is a sectional view showing a modification of the device employing two wedges. .Referring to Figs. l to 4 of the drawings, indicates an axle; B a spring and C a mrt of the chassis of a vehicle. The spring,

in the modification shown, has one eye piving device illustrated, comprises a friction plate having plane surfaces parallel to eaclii other on opposite sides of tie plate. This plate is arranged to be connected to the axle in any suitable manner. 'In the best embodiment of the invention, the friction plate is in the form of a strip of resilient material, such. for example, as spring steel, as indicated at F. Its lower end is secured in any suitable way, as, for example, by inserting the end in the slot of a bracket G, in which slot the friction strip or plate is held by suitable means, as, for example, Jthe bolts g. The bracket G is suitabl secured to the axle, as,for exa1nple,bybolts The friction plate projects through a slot in the bottom of a brake casing, indi'- cated at H, this casing, in the present ex- Vample', having an interlor surface inclined V ing the base surface of the wed may be l secured to the wedge in any suitab e way, as, forex'ample, by rivets, as shown. ln order --the top of the acasing,

that a uiuform area of the friction plate F ma contact with the friction surface of the ,We ge, the upper end of the casing has an openiu through which th plate may groject. suitable cap ha may be secure to as shown in Fig. 2, whereby the upper end of the friction plate F is protected.

Since the tendency of the wedge during l the downward movement of the friction plate is to create a pressure on the. friction plate in.a lateral direction, the casing H is also provided with a'suitable reactlon device arranged to bear vagainst the friction @plate on the side opposite the wedge I and 've a straightthrust reactlon normal .to the "l iction plate and directly in opposition to ithe pressure produced by the wedge I. In

, also rection, from the-bolt there is practically 1,19 rieti uiwardgelativgtothe casing, and, ow'

i springdias: been Pali the present example this reaction device formed as one wall of the casing as indicated at H', and in the best embo iment of the invention the inner face of this wall is provided with a compressible and resilient friction surface, wallY H i, which isrivetedin place, as shown. 'llle casing H is suitably secured to the chassis C of the vehicle, as, for example, b means olf vaboli: K passing through the wa Hand through a hole in the chassis, and provided with 'a nut. The wall. H may be provided 4with a lug, as indicated at hf which bears against the upper edge ofthe chassis frame and thus takes the` shear` in a downward d1- The upper end of the casing H is provided with suitable means for supplyin oil or the like to the frictionsurfaces. n. the present example this means consists of an oil-cup, indicated at`L, securedt the side of the cap ji", by ,means of which oil may be su plied from time to time to the friction sur ces.

.T e operationzofthe mechanism thus far described-isps follows: When the spring B is compressed-the friction plate ll movie e `-frictioi'ial ibetween one o Y fits surfaces andkthe wedge I, the wedge is lifted 4'or in the casing so that O `ap1reciab e retarding action anche .p upwardmoinm ent.l When the spring' be.-

im' jartto vthe isl nan upward 'tioii,fis dependent upon' he extent to hwhich the' springr has been compressed. lf the greatly compressed, its reactoiris greagit will have atendency to iii'ipart ai eat velocity upward to the sprin was .only slightly comlsd' `itbvill ten to give the chassis velocity upwar L 'The upward tend to draw related to the velocity of the fricv as by providing the` with a leather layer or cover h.

y wedge and and the l of the wedge, will ate during such ,s -t reOL' the velocity which it attempts movement of the chassis may be considered, so far as the checking actions are concerned, as if it were a downward movement of the friction plate with the chassis stationary. If the friction plate tends to move downward lwith a high velocity, it will, owinlg to its frictional contact with the wedge the latter downward at a velocit tion p ate. If the friction plate tends to move downward with a low velocity, the wedge I will have a corresponding low velocity. The pull of the friction plate on the wedge constitutes an impulse acting on the wedge and tending to drive the same down the corresponding inclined surface of the Casin? to a greater or lesser extent pro ortiona to the impulse. If the wedge, ine udi'ng its friction surface, were of non-yielding material, the Wedge in all cases 'would stop at substantially t e same point in the cas-` ing, and therefore the pressure transmitted laterally to the friction late by the inclined surfaces, `lould always e the saine. Since, however, t e wedge has a compressible friction surfacealong its base, the wedge may move to different positions downward in the casing, accordin to the initial impulse imparted to the wedgge by the initial movement of the fric'titm plate in a vdownward direction. Cons uently, when 4 the initial velocity of lthe friction lateis great, the wedge will be driiven tig ter and Will compress its friction material to' a greater extent than where the initial impulse was less. The slope4 of Ithe inclined surfaces of ythe length of 'these surfaces relative to the length of the friction surface between the frictionA plate and the compressible material:v of the wedge, are such thatuuder the maximum impulse to which the wedge is subjected, the reaction of the compressiblemateiial, transversely not be sui the wed upward andloosen it-that is to say, e upward resultantof the trans# verse reaction of the compressible material will not overcome the friction between the friction plate inclined surfaces ing. Hence,.the is driven "downward depends upon t e initial velocity of the friction plate relative to the'casin and as soon as the wedge .has been driven down-to bring the corre Y Plessure againstthe friction plate, it Stays in this osition until the friction plate stops, and rough ut the movement maintains on Ythe frictioxh plate substantially the same' pressure as At the commencement-of themovement.v In other words, the ressii're exerted by the wed against the rictihi plate, does not decreaseas the downward velocity of`the friction plate decreases. It willv be seen that by this of the wedge audits cascient to throw andwedgeand between the extent to which-.the wed e "arrangement the braking pressure against the friction plate is determined by the initial velocity of the friction plate relative to the casing, and that whatever the pressure may be, it remains substantially uniform during the continuance of the downward movement of thc friction plate relative to the casing. Furthermore, in the construction just described, the pressure per unit of arca of the friction plate is also substantially uniform, because the area of the friction surfaces in contact with each other remains` constant. When the direction of the friction plate is reversed, the wedge is lifted and the pressure released, with the exce tion of the slight pressure due to the wei t of Ythe wedge itself. Consequently, by t is arrangement the energy due to the recoil of the spring is absorbed in about half the time that it would be if the lateral pressure of the brake against the friction plate varied in proportion to the velocity of the plate downward relative to the casing. Therefore, the oscillation of the chassis due to the reaction of the spring, is damped quickly and without employing any greater maximum pressure against the friction plate than would be the ease where the braking was proportional to the downward velocity of theA friction plate at any instant.

It will be noted that in the example de- -scribed. the friction plate is formed as a strip which has a. relatively considerable portion of its length outside the casing, By making this strip of resilient material, such as spring steel. a relative movement laterally is permitted between the chassis and the` member of the vehicle to which the frictionA plate is attached. because of the bending of the spring strip. The resiliency of this trip causes it to act to a certain extent as a lateral shock absorber.

lfurtheriiiore, the lower end of the frici tion plate may be bifurcated, as indicated at li" iii Fie. With this construction, by a proper timensioning of the bifurcated portion, a greater flexibility of the friction plateis obtainable, thus giving a longer life `to the apparatus. Furthermore, such a bifurcated plate is particularly suitable with vehicles having the spring attached below the axle, as illustrated in Fig, In this modification, the bifurcated ends are joined by a plate f which isola ped beneath the spring by the clamp plate 2 and the spring clips ff, employed in holding the spring to the spring seat.

Referring to the modiification of the invention shown in Fig. 6, it will be seen that the casing indicated at H2, has two inclined face'ii'and contains two wedges, indicated at I` It. T liese wedges have their friction surfaces, h2, 2, arranged to bear on opposite sides of the friction plate. The riction material for these Wedges 1s in this case also coiiipiessible and resilient. It will be noted that with this arrangement, one wedge serves as the reaction device for thel other wedge The slopes of the inclined surfaces, as well as the lengths of Vsaid iiiclines, are such that the resilience of the friction material when compressed to the maximum extent, will not be sufficient to lift and thereby loosen the wedges. .\lso, in this modification the friction plate l does not extend through the top of the casing when the spring is compressed. In this arrangement, the friction area varies during operation, and. hence. the pressure per square unit is \ariable. instead of constant. Since` however, the total pressure due to the wedge is theoretically uniform, the total braking pressure is theoretically uniform. In practice there may be some deviation from this theoretical action, if the friction plate is drawn too fai' downward relative to the \\'e lge,-tliiit is to say. is too short. In this construction the oil may be supplied through the opening L', at the top of the casing.

In the best embodiment of the invention, the friction plate has a width less than the interior of the casing, as will be clear from Fig. 3. This periiiitstlie friction plate to have a reasonable amount of play transverse to its' length during the relative movenient of the spring and chassis, thus allowing for the slight longitudinal movement of these twozparts relative to each other and. at the same time avoiding any rattlewhich otherwise would result from the friction plate striking the casing.

It is particularly to be noted that in these embodiments of the invention, no springs are employed to force the wedge downward. Hence, as the action of gravity on the wedge is uniform, there are no parts to change their characteristics by wear or age. This leads to uniformity and reliability of action of the device, even with long continued use; The friction surfaces may be iven a liberal length and width without un uly enlarging the apparatus, because of the few parts einployed. This adds to the durability of the, apparatus.

It has been found in practice that the apparatus is what may be termed self-adjust;r ing as to the load on the vehicle solit widely varying lea-dsfae properly taken care of during recoil of the spring.

The lubricatino` plied with an oi suitable for use with the friction material. Where the friction material is leather, it is advantageous to em,- ploy neats foot-oil, as this serves to keep the leather in a soft and pliable condition. l `iirtheriiiore, at the time 0f maximum pressure rf The wedge on the friction plate, a small amount of this' oil will be squeezed out of the leather or other friction material,

,device L. Fig.2, isv sup--A yin contact with it.

A having plane surfaces 'surfaces being Y mal to such surface,

and will serve to slight] lubricate the friction plate and leather. llponthe release of the pressure, the leather or other friction material will expand and absorb any free oil remainin on its surface or on the plate In this way, the destruction of -the friction material under the high pressure, which it ma at times be subjected to, is avoided. l

Practical o eration of the apparatus has shown that tliis oiling of the leather friction surfaces is highly important, for with such oiling there seems to be no cutt'in or tearing of the leather by the rubbing o the friction plate, and the wear, if any, is so simili as to be negligible. Furthermore, the recoil of the spring seems to be checked at the'proper rate for comfortable riding with variable loads.

What is claimed is:

l. The combination, with a friction plate and a casing, the casing and plate being arranged for movement relative to each other, of means carried by the casing and aranged to apply a substantially uniform b airing pressure to said friction plate throughout the relative movement in one direction, said means including a device whereby the value of -said pressure is dependent on the initial velocit of said movement.

2. T e combination, with a friction plate on opposite sides, said braking wedge aving one surface inclined and the o posite surface parallel to thesurfacesof t e friction plate, the parallel sui'- face of the wedge having a4 cover of compressible resilient friction material arran ed to come into contact with the corresponding friction plate surface, a casing provided with an inclined surface arranged to coact with the inclined surface of the` Wedge, whereb a.v longitudinal movemeiitof the wedge in one direction will produce a pressure on one surface of the friction plate norand means arranged to contact with the other surface of the friction plate and give only a straight thrust reaction norma to said plate and in direct opposition to said ressu're.

The com ina-tion, with a friction plate having plane surfaces on opposite sides, said surfaces being arallel to each other, of a brakingr wedge avjng one surface inclined and theo posite surface parallel to the-surfaces of t e friction plate, the parallel surface ofthe wedge having a cover of dompressible resilient friction material arranged 'to come into contact with'the corresponding friction late surface, a casing provided with an inclinedisurface arrangedto coact with the inclined surface of the wedge,

whereby La, longitudinal movement of the wedge in `one direction will reduce apressure on Lone surface of the friction plate nor- ,arallel to each other, of av the mal to such surface, and means arranged to 4.. r:The combination, with a frictionplate having plane surfaces on opposite sides, said 754 surfaces being arallel to each other, of a braking wedge liaving one surface inclined and the opposite surface parallel to the surfaces of the friction plate, the parallel surface of the wedge having pressible resilient friction `material arranged to come into contact with the corresponding friction plate surface, a casing provided with an inclined surface arranged 4to coact,

with the inclined surface of the wedge, 35

v.' hereby a lon 'tudinal vmovement of the wedge in one direction will reduce a pressure on one surface of the friction plate normal to such surface, means arranged to contaci` with the other plate and give onl a straight thrust reaction normal to sai plate and in direct o position to said pressure, and an oil inlet diei-V vice carried by the casing and arranged to supply oil' to said compressible resilient fricgli,

tion material. v 5. The combination, with a resilient friction plate having plane surfaces on opposite sides, said surfaces being parallel to each other, of a bralin wedge havin face inclined and t e opposite sur ace parallel to the surfaces of the friction plate, the parallel surface of the wedge having a cover of compressible resilient friction material c orarranged to come into contact with the responding friction4 late surface, a casin provided with an indlined surface arra to coact with the inclined surface `of the wedge, whereby a longitudinal `moveiiient of the wedge in one direction will produce a pressure on one surface ofthe friction plate normal to such surface, means arranged to eontact'with the Iotlieffsurface of the friction late and give only a stra' lit thrust reaction normal to said plate an y, opposition to saidy ressum, the cas' having" an interior wi th greater than t of e friction plate which enters it, whereb a play f said plate wdtltwise is permitt 6. A shock absorber havin plate F, the wedge I having t e leather surace i' arranged to contact with one side ofplate F, thecesing H arran to coact with the wedge and carrying a eather altrface h arranged tof contact withth'e side of thelplateF, andmeans 'for securing plate F, thev wedge I having Y e leather suriitu a cover of com- 30 surface of the friction 90 one surmi) ,in direct the friction pressure, said means hav- 70 A V other faefgi arranged to Contact with one Side of Y'h lfolate F, the casing H arranged to couct with the Wedge and curlying :.1 lvztther surfeed/1 arranged to Contact with the other side of the plete F, the oil receptacle I for oiling the leather surfaces L and e', and means for securing the easing H and the friction plate F to the vehicle, substantially es described.

8. A shock absorber having the friction plete F, the wedge I having the leather surface i arranged to contact with one side of the plate F, the casing H arranged to coact with the Wedge and carrying e leather surface zl arranged to contacty with the other side of the plate F, Said casing having the lng?r It and the bolt K for holdmg it on the vuhlele frame, and means for holding-the friction plete F to move with the axle, substentinlly as described.

In testimony whereof, I have hereunto set my hand.

WILLIAM R. RENO. 

